Smell sensor



FIG. 1 is a front view of a smell sensor, showing our new design;

FIG. 2 is a top view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a front perspective view thereof; and,

FIG. 6 is a back perspective view thereof.

The broken lines in the figures illustrate the portions of the design that form no part of the claimed design. 

CLAIM The ornamental design for a smell sensor, as shown and described. 